Collapsible connecting rod



May 2, 1939. C, C SWTH f 2,156,548

COLLAPS IBLE CONNECTING ROD WITNESSE INVENTOR: @mmm/,f e- 5mm,

BY L M@ WW TTORNEYS.

May 2, 1939 c. c. SMITH 2,156,548

COLLAPS IBLE CONNECT ING ROD Filed Dec. 8, 3.936 5 Sheets-Sheet 2 WITNESSES:

m LZ May 2, 1939. V c. C. SMITH 2,156,548

y COLLAPSIBLE CONNECT-ING ROD Filed Deo. 8, 1936 5 Sheets-Sheet 3 2a FIG- W.

WITNESSES' INVENTOR:

K i TORNEYS.

Patented May 2, 1939 UNITED STATES PATENT OFFICE Clarence C. Smith, Chicago, Ill., assignor to Union Special Machine Company, Chicago, Ill., a corporation of Illinois Application December 8, 1936, Serial No. 114,728

11 Claims.

This invention relates to collapsible connecting rods useful for example, in connection with looper mechanisms of chain stitch sewing machines after the manner disclosed in U. S. Patent'No. 1,850,949, granted to Frederick F. Zeier and the present applicant on March 22, 1932 to enable retraction of the looper from its normal sphere of operation in relation to the needle, for convenience of easy threading. For the purpose of maintaining the connecting rod of the patent in extended position, there is provided a sleeve which overlaps the pivot joint between the two rod components, and which must be shifted axially against spring pressure before the rod can be collapsed. Due to the smallness of the parts,

close contiguity of the associated elements of the looper mechanism and the lack of room for the fingers, manipulation of the sleeve, preparatory to collapsing the rod, is not only comparatively difficult, but time consuming.

My present invention is directed toward overcoming the above draw backs, which objective I realize in practice, as hereinafter more fully set forth through provision of an articulated connecting rod which can be quickly buckled or collapsed by mere pressure of a finger upon one side thereof and likewise extended by lateral pressure from the other side, and which, through cooperation of spring means on one of its components with angularly-spaced tangential flats at the pivot joint end of the other component, is yieldingly maintained against the possibility of accidental displacement from its extended and collapsed positions.

Other objects and attendant advantages will appear from the following detailed description of the attached drawings whereof Fig. I is a fragmentary view, in longitudinal section, of a chain-stitch sewing machine having looper mechanism with a collapsible connecting rod conveniently embodying my invention in one form.

Fig. II is a plan section of the machine viewed as indicated by the arrows II-II in Fig. I.

Fig. III is a view corresponding to Fig. I with the connecting rod collapsed. f

Figs. IV and V are detail views of the connecting rod on a larger scale respectively showing it in extended and collapsed condition.

Fig. VI is a cross section of the rod taken as indicated by the arrows VI--VI in Fig. IV, and

Figs. VII and VIII are views like Figs. IV and V showing an alternative form of my improved connecting rod.

The sewing machine illustrated in Figs, I-III (Cl. 'Z4-579) for convenience of exemplifying my invention is, generally speaking, of well-known construction in that it comprises a needle l, and a looper 2 which cooperates with said needle to produce chain stitches in fabric (not illustrated) advanced along the work support 3 of the machine by a toothed feed dog 4 mounted on a feed bar 5. The necessary feed and lift movements are imparted to the feed bar 5 from the main longitudinal shaft 6 of the machine through suitable connections which need not be described since they are not pertinent to my present invention. The looper carrier 1 is pivotally connected at 8 for movement crosswise of the direction of feed, to one side of a sleeve 9 secured to a rock shaft Il! whereof the ends are journaled in renewable bushings l2 and I3 in pendant bearing bracket lugs I4 and I5 of the work support 3. Lateral needle avoiding movements are communicated tothe looper 2 from an eccentric I6 on the main shaft 6, the strap l1 of said eccentric being connected to an arm I8 on the rock shaft l0, see Fig. II. VThe means for imparting loop-taking and shedding movements to the looper 2 include a crank I9 on the main shaft 6; a pitman 20 connecting the crank to the horizontal arm 2l of a bell crank rocker 22 on a transverse shaft 23 whereof the ends are journaled in renewable bushings 24, 25 supported by spaced projections 26 and 21 of the bearing bracket lug l5; and a connecting rod 28 coordinating ball pivot studs 29 and 3D-respectively on the looper carrier 1 and the vertical arm 3| of the bell crank rocker 22.

It is with the construction of the connecting rod 28 that the present invention is more especially concerned. As shown, therod 28 has two main components 32, 33 which are interpivoted at 34 so that it can be collapsed to retract the looper 2 from its normal sphere of operation adjacent the needle I for convenience of threading. The component 32, it will be observed, is formed with a tapped cylindric portion 35 in which is engaged the right hand threaded end of a coupling screw 36. The opposite left hand threaded end of lthis screw 36 similarly engages within the tapped socket portion 31 of a split end bearing member 38 which embraces the lateral ball stud 29 on the looper carrier 1. Obviously, by turning the coupling screw 36 in one direction or the other, the connecting rod 28 can be lengthened or shortened to adjust the looper in respect to the needle I. The jamb nuts shown at 39 and All serve to fix the screw 36 in adjusted positions. The portions of the rod componentV 32 inwardly beyond and below the cylindric portion 35 are continuously slotted as at 4| and 42 (Fig. V) to provide a receiving clevis for the pivot joint end of the component 33, and a receiving recess for the retroverted end 43 of a leaf spring 44. Adjacent the pivot pin 34, the side cheeks of the component 32 are definitely spaced by a collar 45 which is interposed in the interval 4| and which surrounds a transverse securing rivet 48. A pin 4l extending crosswise of the slotted portion 42 of the component 32 and registering with a transverse notch 48 in the retroverted end 43 of the spring 44, is relied upon to rmly anchor said spring with its retroverted end bearing substantially throughout its length against the bottom of the cylindric portion 35 as shown in Figs. V and VI. The free end 49 of the spring 44 is bent into lengthwise parallelism with the component 32 and provides a flat bearing surface, which, by cooperation respectively with angularly spaced tangential iiats 59 and 5i at the pivot joint end of the component 33 to hold the rod 28 yieldingly but denitely in extended and collapsed positions as shown in Figs. IV and V. Accurate alignment of the components 32 and 33 when the rod 28 is extended as in Fig. IV, is insured by contact of an abutment lug 52 on the component 33 with the free end of the spring 44; and by the same means the rod is restricted to collapse in one direction. As shown, the component 33 is formed with a split bearing 53 which engages the ball stud 3!! on the bell crank rocker arm 3|. Normally, with the rod 28 in extended position, the pivot 34 interconnecting the rod components and the bearing apertures for the studs 29 and 3i) all lie in a straight line.

Due to the described construction it is possible to collapse the rod 28 when access to the looper 2 is desired for threading, simply by pressing downward upon it at the region 0I" the pivot joint 34 with a nger, and to subsequently restore it to its normal extended position in a like manner by upward pressure at the region of said pivot 34. The only effort required in either instance is to overcome the slight resistance of the spring 44, which, as before stated serves, by cooperation with its fiat end portion 49 respectively with the ats 5G and 5l on the component 33 to yieldingly hold the rod in its extended and collapsed positions.

In the alternative embodiment of my invention shown in Figs. VII and VIII, the component 32a of the connecting rod 28 is made tubular and formed with a clevis at one end, the bore of the tubular portion being threaded at one end to receive the coupling screw 35a. The remainder of the bore in the component 32a is smooth. and occupied by a helical compression spring 44a, which, at one end bears against an adjustable abutment screw 55 and which, at the other end engages Within the hollow of a piston plunger 49a whereof the outer face is square and flat and adapted to cooperate with the angularly-spaced tangential flats 50a, Sla of the component 33a. In this instance, the rod is restrained against collapse upwardly by engagement of the lower corner of the tubular portion of the component 32a with the crosswise ilat 50a; of the component 33a, as shown in Fig. VII. In all other respects, the modied construction is like that of the rst described embodiment and in order to dispense with the necessity for repetitive description the corresponding parts have been identied by the same reference numerals previously used with the letter a added in each instance for the purpose of distinction.

While I have herein illustrated and described my improved collapsible connecting rod in association with looper mechanism for sewing machines, it is obvious that the same can be used with attainment of advantages equal in all respects to those hereinbefore pointed out in other mechanisms of sewing machines as well as in other kinds of machinery. The appended claims are accordingly to be interpreted with this thought in mind.

Having thus described my invention, I claim:

1. A collapsible connecting rod comprising two components, each having a bearing aperture, a pivot interconnecting said components, the axis of said pivot and said bearing apertures normally lying in a straight line, one of said components being tubular; a flat-ended spring-pressed plunger within the tubular component adapted, by cooperation respectively with angularlyspaced tangential iiats at the pivot end of the other component, to yieldingly maintain the rod in extended or in collapsed condition.

2. A collapsible connecting rod comprising two components, each having a bearing aperture, a pivot interconnecting said components, the axis of said pivot and said bearing apertures normally lying in a straight line, one of said components being tubular; a flat-ended spring-pressed plunger within the tubular component adapted, by cooperation respectively with angularlyspaced tangential flats at the pivot end of the other component, to yieldingly maintain the rod in extended or in collapsed condition; and means whereby the rod is ccnned to collapse in one direction.

3. A collapsible connecting rod comprising two components, each having a bearing aperture, a pivot interconnecting said components, the axis of said pivot and said bearing apertures normally lying in a straight line, one of said components having angularly-arranged tangential ats at its pivot end, and yielding means on the other of said components having a flat bearing surface for contacting respectively with the :dats on the first mentioned component to maintain the rod in extended position or in collapsed position.

4. A collapsible connecting rod comprising two components, each having a bearing aperture, a pivot interconnecting said components, the axis of said pivot and said bearing apertures normally lying in a straight line, one of said components having angularly-arranged tangential flats at its pivot end, and a spring on the other of said components having a flat bearing surface for contacting respectively with the flats the i'lrstmentioned component to maintain the rod in extended position or in collapsed condition.

5. A collapsible connecting rod comprising two components, each having a bearing aperture, a pivot interconnecting said components, the axis of said pivot and said bearing apertures normally lying in a straight line, one of said components having singularly-arranged tangential ats at its pivot end, yielding means on the other of said components having a at bearing surface for contacting respectively with the flats on the first mentioned component to maintain the rod in extended position or in collapsed position, and means for restricting the rod to collapse in one direction.

6. A collapsible connecting rod comprising two components, each having a bearing aperture, a pivot interconnecting said components, the axis of said pivot and said bearing apertures normally lying in a straight line, one of said components having angularly-arranged tangential flats at its pivot end, yielding means on the other of said components having a flat bearing surface for contacting respectively with the flats on the first mentioned component to maintain the rod in extended position or in collapsed position, and means whereby the rod can be' adjusted for length.

'7. A collapsible connecting rod comprising two components, each having a bearing aperture, a pivot interconnecting said components, the axis of said pivot and said bearing apertures normally lying in a straight line, one of said components having angularly-arranged tangential flats at its pivot end, yielding means on the other of said components'having a flat bearing surface for contacting respectively with the flats on the first mentioned component to maintain the rod in extended position or in collapsed position, a supplemental end member associated with one of the components and a screw connecting it to said components whereby the rod can be adjusted for length.

8. A collapsible connecting rod comprising two components, each having a bearing aperture, a pivot interconnecting said components, the axis of said pivot and said bearing apertures normally lying in a straight line, one of said components having angularly-arranged tangential flats at its pivot end, yielding means on the other of said components having a iiat bearing surface for contacting respectively with the flats on the rst mentioned component to maintain the rod in extended position or in collapsed position, a supplemental end member associated with one of the rod components, and a screw having right and left hand threaded end portions connecting said member to said component whereby the rod can be adjusted for length.

9. A collapsible connecting rod comprising two components, each having a bearing aperture, a pivot interconnecting said components, the axis of said pivot and said bearing apertures normally lying in a straight line, one of said components having angularly-arranged tangential ats at its pivot end, and a longitudinal leaf spring on the other component having a flat at its free end for contacting respectively with the flats on the rst mentioned component to maintain the rod in extended position or in collapsed position.

10, A collapsible connecting rod comprising two components, each having a bearing aperture, a pivot interconnecting said components, the axis of said pivot and said bearing apertures normally lying in a straight line, one of said components having angularly-arranged tangential iiats at its pivot end, and a longitudinal leaf spring on the other component having a flat at its free end for contacting respectively with the flats on the first mentioned component to maintain the rod in extended position or in its collapsed position, and an abutment on the second mentioned component for engaging the free end of the spring to confine the rod to collapse in one direction.

l1. A collapsible connecting rod comprising two components, each having a bearing aperture, a pivot interconnecting said components, the axis of said pivot and said bearing apertures normally lying in a straight line, one of said components having angularly-arranged tangential flats at its pivot end, and yielding means on the other of said components having a nat bearing surface for contacting respectively with the flats on the rst mentioned component to maintain the rod extended with its components in axial alignment against the possibility of accidental buckling under endwise pressure, or to maintain the rod collapsed with its components disposed in angular relation.

CLARENCE C. SMITH. 

